The present invention relates to dimming control systems employing interchangeable dimmer modules and enclosures for mounting such dimmer modules. More particularly, the present invention relates to a unique dimmer module architecture employing on board intelligence for dimming control and a rack mounting system for the intelligent dimmer modules employing dual communications control modules for communication with individual dimmer modules in the rack and non-volatile memory in the rack backplane for storage of configuration information and independent operating parameters.
Lighting control systems for architectural, theatrical and movie/television applications typically incorporate numerous individual dimmer circuits, which are rack mounted at central locations for control of disbursed individual and grouped incandescent or inductive loads. Conventional dimming communications protocols have been developed for various input communications devices to communicate with rack mounted dimmers and typically individual racks incorporate a controller for receiving such commands and distributing commands to the individual dimmer modules.
Various technologies have been employed for individual dimmers including choke based and electronic dimmer systems. Control of both types of systems has been accomplished using pulse width modulated (PWM) control approaches. Consolidation of processing in a centralized controller for large numbers of dimmer control circuits creates significant complexity in the controller. It is therefore desirable to distribute control functions while centralizing communications for dimmer rack systems. Such distributed processing is also particularly advantageous with newly developed lighting control systems employing local area networks for command and control communication.
Dimming racks in the prior art typically support numerous dimmer modules. To allow flexibility in lighting requirements, dimmer racks must support dimmer modules having varying power ratings and physical interconnection requirements for load outputs. It is therefore desirable for dimmer racks to incorporate means for assuring mating of properly configured dimmer modules with compatible load and wiring configurations within the rack while maintaining commonality of interface structure to reduce cost and complexity in the rack system. The capability to preconfigure racks with specific dimmer module information and to provide redundant control capability for system failures, panic mode operations and independent control of rack based looks for lighting controlled by the racks is desirable.
The present invention provides the desired features overcoming deficiencies in the prior art while maintaining produceability of both dimmer racks and dimmer modules for cost considerations and commonality with prior art control systems.
The dimming control system with distributed command processing comprises a rack having a plurality of slots for dimmer modules, each slot having supports formed by a punch and break process on an inner sheet metal panel of the walls of the rack. Each slot incorporates load connectors and communication board connectors mounted in spaced relation from one wall of the rack to engage mating connectors in inserted dimmer modules. Power bus connection is accomplished by multiple blade conductors mounted adjacent one wall of the rack opposite the wall supporting the load and board connectors.
A pull out tray located at the bottom of the rack receives two control modules providing data communications for level and configuration control to the individual dimmers in the dimmer modules. A backplane for the rack resides on the rear wall of the pull out tray allowing easy access to backplane connectors by removal of the control modules and extraction of the tray. A non-volatile memory system present in the backplane stores rack configuration data and dimmer looks for independent operation of the rack dimmers. This data is retained in the rack after setup even if control modules are removed or exchange.
Dimmer Modules in the system incorporate a chassis engaged by the slot supports in the rack. A side load spring mounted on one side of the chassis urges the dimmer module against the opposite side wall of the rack thereby creating a high tolerance datum for board connector placement. A floating power connector is mounted in the chassis to receive the power bus blade. A full slot height lobed leaf spring for the side load spring prevents airflow in the rack slot outside the vented dimmer module itself and also provides secondary function as a ground contact. A three point keying system on the high tolerance wall of the rack prevents insertion of improperly rated dimmer modules in prewired slots.
Each dimmer module incorporates a power device having an on board microcontroller for dimming level control. Dimmer levels are provided as serial communication from the control modules in the rack to the dimmer module microcontroller, which provides local generation of PWM gating for SCR control in the power device. Internal intelligence in the dimmer module provided by the microcontroller allows individual dimmer control, diagnostics and calibration functions not possible in the prior art including module presence detection, type identification, load current sensing, open load sensing, circuit breaker open sensing, increased power control accuracy and individual temperature monitoring and control. In addition, panic switching is accomplished at each individual module through detection of DIP switches at each slot location by the microcontroller, independent of the presence or status of any control module in the rack.
Local rack control is accomplished through a hand held controller removably mounted in the door of the rack with a display visible through a window in the door for monitoring with the door closed and the rack in operation. Connection through the backplane connectors is provided for industry standard dimming control protocol and local area network control system.